Lifting device



R. C. FLYNN LIFTING DEVICE Dec. 2?, 1949 2 Sheets-Sheet 1 Filed Oct. 25, 1945 I flaflynn Decu 27, 1949 c, FLYNN 2,492,853

LIF'I'ING DEVICE Filed Oct. 25 1945 2 Sheets-Sheet 2 R an, 72

Patented Dec. 27,

UNITED STATES PATENT OFFICE 2,492,853 L IFTI NG DEVICE Robert C. Flynn, Houston, Tex.

Application October 23, 1945, Serial No. 623,996

This invention relates to a lifting device and it is primarily an object of the invention to provide a device of this kind comprising a base member and a work-engaging member operatively connected by pivoted levers in a manner whereby the desired raising and lowering of the lifting member is effected upon rotation of an operating shaft.

Furthermore, it is an object of the invention to provide a device of thiskind including a base member and a lifting member operatively connected by bars assembled as in a parallelogram and in a manner whereby, when the lifting member is atits maximum height, the parallelogram center lines will be in parallel, thereby forming two parallelograms at the highest point of the lifting member.

A still further object of the invention is to provide a device of this kind including a base member and a lifting member operatively connected by bars which form two parallelograms at the lowest point and when the lifting member is at its highest point but at no time forming a parallelogram within an action of the bars of 78 degrees.

An additional object of the invention is to provide a device of this kind comprising a base member and a lifting member operatively connected by two sets of bars in a manner whereby one set of bars forms a parallelogram below the horizontal center line and the second set of bars forms a parallelogram above the horizontal center line.

A still further object of the invention is to provide a device of this kind including a base member and a lifting member constructed and assembled in a manner wherein the action of the device is not that of a complete right angle but is variable between 12 degrees and 90 degrees oiT the horizontal center line.

The invention consists in the details of construction and in the combination and arrangement of the several parts of my improved lifting device whereby certain important advantages are attained as will be hereinafter more fully set forth.

In order that my invention may be better understood, I will now proceed to describe the same with reference to the accompanying drawings, wherein:

Figure l is a view in side elevation of a lifting device constructed in accordance with an embodiment of the invention and in its lowermost adjustment;

1 Claim. (Cl. 254126) Figure 2 is a vertical sectional view showing the device in its uppermost adjustment;

Figure 3 is a view in end elevation of the device as illustrated in Figure 1;

Figure 4 is a fragmentary detail sectional view taken on the line l'4 of Figure 2; and

Figure 5 is a fragmentary view partly in section and partly in top plan showing the engagement of the operating bar with the shaft.

In the embodiment of the invention as illustrated in the accompanying drawings, B denotes a base member and L a lifting member operatively connected in a manner whereby desired up and down movement of the lifting member L may be readily effected upon rotation of the heavy duty operating screw S.

The base member B includes a bottom plate I of desired dimensions and which is provided with the transversely spaced upstanding side plates 2 arranged in parallelism with each other and with the longitudinal axis of the plate I. In the present embodiment of the invention, these plates 2 are equidistantly spaced at opposite sides of such longitudinal axis.

Pivotally connected, as at 3 and 4, with the opposite end portions of each of the plates 2 are the inner extremities of the elongated bars 5 and 6 respectively. These bars 5 and 6 are arranged one above the other and the pivotal connections 4 of the upper bars 6 are disposed inwardly of the pivotal connections 3 of the lower bars 5.

It is also to be particularly pointed out that each set of pivotal connections 3 and 4 is of the same relative arrangement as all of the others. All of the bars 5 and 6 are of the same lengths and the outer extremities of each set of bars 5 and B are pivotally connected, as at i, with a plate 8 welded to the side face of a knuckle block 9.

Freely disposed through one of the knuckle blocks 9 and threading through the other is an elongated heavy duty screw S whereby, upon requisite rotation of the screw S, the knuckle blocks 9 will be caused to move in unison either one toward the other or in the opposite directions.

Keyed, as at Ill, to an extended end portion of the screw S adjacent to the free knuckle block 9 is a tubular member or sleeve H projecting a desired distance beyond the adjacent end portion of the screw S. This extended portion is provided with an opening I2 diametrically opposed to the inner portion of an open slot l4 into which are adapted to be engaged a cross head I 5 carried by an end portion of an elongated operating bar IE to be rotated in any manner desired, as by a hand crank.

Interposed between the inner end of the tubular member or sleeve II and the outer face of the adjacent knuckle block 9 is an antifriction assembly I! which may be as desired.

Pivotally connected at the upper point 1 with the plates 8 of the knuckle blocks 9 are the outer end portions of the lower top bars l8 which are disposed inwardly and upwardly .which have their inner extremities pivotally connected, as at E9, with the lower portions of the transversely spaced plates 2|] comprised in the lifting memb'e'r L and depending from the top or work-engaging plate 2! of said lifting member L.

Directly above the pivotal mounting 1 "for .the lower bars 5 are pivotally engagedas at 2!, the outer ends of the upper top harem which are disposed substantially in parallelism with .the bars l8 and have their inner extremities pivotally coneeee. as at new; the pla e we he i t member veetverdl 911 99 me t 3 en9'di1 e l 51 91 the P .3 briihe Pet T e yete are directly above the pivots g.

$129. ren r turn n e he s ew 5 t i s er ,be ra e a d he ex ent o arthenware mey iiient b in e ba s it an .3 verti a y n a l e s r it the are 1 :3 21d @2 F11 ta s and [3 in itudi al al gnmen he "l erm st downwa meyei neetei ne.. iee reenter i b e te 9 th bars .23 an iifi th tars 1. and 5 1 respec ivel 'l ti e dev ce e m ris n a a e m m er.

. sai member knu kl .hleeks inei nte ormove- ,ment n and by the s rew pars piv tally cone ted o ari be ween the lease membe and set, each set of bars consisting .of two outside pairs and two inside pairs, each outside pair of bars having spaced ends between which a member is pivotally joined, the opposite ends of each outside pair having a knuckle block therebetween, vertically spaced pivot on the knuckle blocks engaged by the said opposite ends of the outside bars of the upper and lower sets, the pivots for the spaced ends of one pair of bars and the pivots for the spaced ends of the bars joined 'to the'same 'member being widely horizontally spaced and on opposite sides of the vertical center of the device, each inside pair of bars is piiiotally joined, the opposite ends of each insidepair having a knuckle block therebetween,

the lee sene t9 and hem enthe lileeks an h i ting member the. ba s vR ne tire sets, the bar 9 ee tet be n abexe the-pars of he othe pivots between each knuckle block and the said opposite ends'of the inside pairs of bars adjacent thereto and forming a single axis transversely of the block on which the inside bars of the two sets turn, the pivots between the mside' bars the rnembeis adjacent thereto being" seif 'clos'ei to the said. ,ve'rtical center of the device thafi'the said fwidely spaced pivots, the

pivots forming the sin le axes being set closer re d e sa d 'yeaicai ciiterpf't'he' device than the amateur yertically spaced pivots to which the aillls i dbar s air bdrlnbted, 2.11 Of thfibfiJ-S 0f the sets bein parallel when the lifting member is s ine limit b i s p ard e ire n 'and m een for rotating'the screw to inove the blocks inw rd efid u e lih9 fll i ill eie en e a e .1 re r i h file of this patent:

en re A? dum er N353??? 1,352,630 -Lafrance Dec. 21, 1920 ltgiifl i 17 1 2 

